public double GetCriticalStress()
{
double F_e = GetFe_();
double lamda_1 = GetLambda1();
double lamda_2 = GetLambda2();
double lamda_eq = GetLambda_eq(F_e);
double E = Material.E;
MaterialBucklingConstantProvider bcf = new MaterialBucklingConstantProvider(BucklingType.FlexuralCompression, this.SubElementType, Material, WeldCase);
double C_p = bcf.C;
double B_p = bcf.B;
double k_2 = bcf.k_2;
double F_b = 0;
if (lamda_eq <= lamda_1)
{
F_b = ((M_np) / (S_xc));
}
else if (lamda_eq < lamda_2)
{
F_b = ((M_np) / (S_xc)) - (((M_np) / (S_xc)) - ((Math.Pow(Math.PI, 2) * E) / (Math.Pow(C_p, 2)))) * (((lamda_eq - lamda_1) / (C_p - lamda_1)));
}
else
{
F_b = ((k_2 * Math.Sqrt(B_p * E)) / (lamda_eq));
}
return(F_b);
}
private double GetLambda2()
{
MaterialBucklingConstantProvider bcf = new MaterialBucklingConstantProvider(BucklingType.FlexuralCompression, this.SubElementType, Material, WeldCase);
double C_p = bcf.C;
double lambda2 = C_p;
return(lambda2);
}
public void AluminumShapeReturnsBucklingConstant_C_p()
{
AluminumMaterial mat = new AluminumMaterial("6061", "T6", "0.062 or greater", "std structural profile");
MaterialBucklingConstantProvider bcf = new MaterialBucklingConstantProvider(BucklingType.FlexuralCompression, SubElementType.Flat, mat, Aluminum.AA.Entities.WeldCase.NotAffected);
double C_p = bcf.C;
double refValue = 66.9; // from Design Manual
double actualTolerance = EvaluateActualTolerance(C_p, refValue);
Assert.LessOrEqual(actualTolerance, tolerance);
}
private double GetLambda1()
{
MaterialBucklingConstantProvider bcf = new MaterialBucklingConstantProvider(BucklingType.FlexuralCompression, this.SubElementType, Material, WeldCase);
double F_cy = this.Material.F_cy;
double B_p = bcf.B;
double D_p = bcf.D;
double lambda_1 = ((B_p - F_cy) / (D_p));
return(lambda_1);
}